Speed reducer for retractable screen systems

ABSTRACT

A retractable screen mechanism is disclosed for covering an opening. The retractable screen mechanism comprises two tracks mounted on opposing sides of the opening. A screen comprises a screen material mounted on a frame having two flexible opposing sides corresponding to and adapted to engage the two tracks. A spool mechanism extends between the flexible opposing sides and engages a third side of the frame. The screen winds up on the spool mechanism. The spool mechanism is biased to the wind up position. The spool mechanism has a speed reducer which comprises a resistance structure moving through a viscous fluid to reduce the speed of the biased screen when moving to the wind up position.

TECHNICAL FIELD

[0001] This invention relates generally to the field of speed reducersused to slow movement, and, more particularly, to a speed reducer for aretractable doors and windows or any other retractable device used tocontrol light and movement of people and/or insects.

BACKGROUND OF THE INVENTION

[0002] Retractable screen systems have become very popular in recentyears. Such systems provide a screen which is typically extended andlatched to cover and opening such as a door or a window. These systemsemploy a tracks to guide the screen and provide a seal against theelements. The screens are made of a flexible material mounted on aridged frame adapted to engage the tracks but which allow the screen tobe wound up on a spool when not in use. This provides more compactstorage that either previously available sliding screens or hingedscreen doors of the even earlier prior art.

[0003] However, the present day systems employ spools which are springloaded and biased to the closed position. Thus, once the screen isunlatched, it will rewind to the spool automatically. Unfortunately,such spring loaded systems rewind very quickly and sometimes painfullycatch fingers or other extremities. Thus, there is a need for amechanism to reduce the retraction speed of such systems to avoid suchdifficulties.

[0004] The present invention meets this need.

SUMMARY OF THE INVENTION

[0005] It is an object of this invention to provide a speed reducer fora retractable doors and windows or any other retractable device used tocontrol light and movement of people and/or insects.

[0006] Further objects and advantages of the invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize this invention will be pointed out withparticularly in the claims annexed to and forming a part of thisspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention may be more readily described by referenceto the accompanying drawings in which:

[0008]FIG. 1 is a perspective view of a screen system in a closedposition;

[0009]FIG. 2 is an exploded perspective view of a screen systememploying the present invention;

[0010]FIG. 3 is a close up view of one embodiment of a speed reducer ofthe present invention;

[0011]FIG. 4 is a cross sectional view of the embodiment of FIG. 3 takenalong lines 4-4;

[0012]FIG. 5 is a cross sectional view of the embodiment of FIG. 4 takenalong lines 5-5;

[0013]FIG. 6 is an exploded view of the speed reducer of FIG. 3; and

[0014]FIG. 7 is an alternate embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] As best seen in FIGS. 2-6, the present invention is a speedreducer 26 incorporated into a screen system 10. A screen system 10 inan extended position is best seen in FIG. 1. Screen system 10 comprisesa screen 12 which is typically extended and latched to cover and opening14 such as a door or a window. Screen system 10 employs a first track 16and an opposing second track 18 which are adapted to guide screen 12 andprovide a seal against the elements.

[0016] Screen 12 is generally comprised of are made of a flexible screenmaterial 20, for example, a fabric, mounted on a frame 22 having aflexible first side 22 a and a flexible opposing second side 22 badapted to engage tracks 16 and 18. Frame 22 and material 20 allowscreen 12 to be wound up on a spool mechanism 24 when not in use. Theability to wind up screen 12 provides for more compact storage thaneither previously available slidings screens or hinged screen doors ofthe even earlier prior art. A latch mechanism 25 mounted to one side 22c of frame 22, side 22 c extending between sides 22 a and 22 b, engagesa corresponding latching mechanism 29 mounted on the corresponding sideof opening 14 holds screen 12 in the extended or unwound positionillustrated in FIG. 1 when desired.

[0017] To move screen 12 to a rewound position whereby opening 14 isuncovered, latch mechanism 25 is disengaged by the user. Spool mechanism24 is biased to the rewound position whereby once screen 12 isunlatched, screen 12 rewinds to spool mechanism 24 automatically.

[0018] As shown in FIG. 2, spool mechanism 24 comprises an elongatedhousing 28 having a U-shaped profile and a rotating axle 30 containedtherein. A plate 32 covers the open side end of housing 28 except for anslot 34 while two caps 36 provide and support therefor. A side 22 d offrame 22 opposite side 22 c is attached to axle 20 while screen 12extends through slot 34. Latch mechanism 25 itself prevents screen 12from being completely rewound onto axle 30. Side 22 c is, preferably,adapted to cover slot 34 to prevent entry of dirt, insects and the likewhen screen 12 is in rewound position.

[0019] Axle 30 engages a constant tension spring mechanism 31 at one endthereof. As discussed, spring mechanism 31 is biased to hold screen 12in the rewound position. The mechanisms discussed to this point are wellknown in the prior art.

[0020] The present invention is the addition of a speed reducermechanism 26 at the end of axle 30 opposite spring mechanism 31. In theprior art, speed reducer mechanism 26 is normally a bushing or the like(not shown) which allows for free rotation of axle 30 without speedreduction. The heart of the present invention is the use of thestructure moving through a viscous fluid to reduce the speed of thescreen 12 movement.

[0021] Turning now to FIGS. 3-6, the presently preferred embodiment ofspeed reducer mechanism 26 comprises a cylindrical, hollow ribbedhousing 40 having a shaft 42 extending coaxially and rotatable mountedtherewithin. A plurality of vane blades 44 extending laterally fromshaft 42. Housing 40 includes threading 46 a at one open end thereofwhich is adapted to mate with corresponding threading 46 b on a cap 48to close said open end. An o-ring 50 provides a seal between housing 40and cap 48.

[0022] At the opposing end of housing 40, a recess 52 is adapted toreceive an end 54 f shaft 42 and allow shaft 42 to rotate with respectto housing 40. A bushing 56 is mounted to the opposite end of shaft 42and extends upwardly through cap 48. O-ring 58 in combination with cap48 and bushing 56 provides a liquid proof seal between the interior andexterior of housing 40 while allowing shaft 42 to rotate with respect tohousing 40. An upper end 57 of shaft 42 extends upwardly from housing40.

[0023] Housing 40 is filled with a liquid substance, preferably aviscous material 60 such as a hydraulic oil. The combination of vaneblades 44 and viscous material 60 provides resistance to rotation ofshaft 42 and housing 40. Further resistance is provided in the mostpreferred embodiment by adding ribs 61 extending inwardly from housing40 as best seen in FIG. 5. Ribs 61 add turbulence to the flow of theviscous material 60 which increases the resistance thereof. To furtheradd resistance, ribs 61 are bent slightly in one direction of the other.

[0024] As best seen in FIG. 5, vane blades 44 are not radially orientedbut instead curve away from that radial orientation in the clockwisedirection as viewed in FIG. 5. The curvatures of blades 44 allows lessturbulent hydraulic flow when vane blades 44 rotate in acounterclockwise direction as opposed to a clockwise direction. In thepreferred embodiment, the counterclockwise direction is used to movescreen 12 from the rewound position to the extended position while theadded resistance is used to impede the movement of screen 12 from theextend position to the rewound position against the pull of spring 31.

[0025] Housing 40 is, preferably, mounted to the interior of axle 30 androtates therewith. Upper end 57 is fixedly mounted to cap 36 and doesnot rotate. Thus, housing 40 and axle 30 rotate about a fixed shaft 42to provide the reduction in speed.

[0026] Turning now to FIG. 7, an alternate embodiment of the presentinvention is illustrated. This embodiment includes a housing 70 having acap 71 at one end thereof and a jackscrew 72 rotatably received withinhousing 70 with an upper end 74 extending through cap 72. A disk 76having two tabs which ride in tracks along the interior of housing 70 isrotatably received on jackscrew 72 and, as jackscrew 72 rotates, travelsupwardly and downwardly thereon depending upon the rotational directionof jackscrew 72. Housing 70 is filled with viscous material 60 providingresistance to the travel of disk 76 therethrough.

[0027] Although only certain embodiments have been illustrated anddescribed, it will be apparent to those skilled in the art that viscouschanges and modifications may be made therein without departing from thespirit of the invention or from the scope of the appended claims.

What is claimed is:
 1. A retractable screen mechanism for covering anopening, the retractable screen mechanism comprising: two tracks mountedon opposing sides of the opening, a screen comprising a screen materialmounted on a frame having two flexible opposing sides corresponding toand adapted to engage the two tracks, a spool mechanism extendingbetween the flexible opposing sides and engaging a third side of theframe, the screen being adapted to wind up on the spool mechanism, thespool mechanism being biased to the wind up position, the spoolmechanism having a speed reducer comprising a resistance structuremoving through a viscous fluid to reduce the speed of the biased screenwhen moving to the wind up position.
 2. The retractable screen mechanismof claim 1 further comprising a latch mechanism mounted to a fourth sideof frame opposite the third side, the fourth side extending between thetwo flexible opposing sides, the latch mechanism engaging acorresponding latching mechanism mounted on the corresponding side ofthe opening to latch the screen in an extended position.
 3. Theretractable screen mechanism of claim 1 wherein the spool mechanismcomprises an elongated housing having a U-shaped profile and a rotatingaxle contained therein and a plate partially covering the open side endof the elongated housing, the elongated housing and the plate defining aslot, the third side of the screen extending through the slot to engagethe axle, the axle engaging a spring mechanism at one end thereof, thespring mechanism being biased to hold the screen in the wind upposition, the speed reducer being mounted at the other end of the axle.4. The retractable screen mechanism of claim 3 wherein the speed reducercomprises a hollow housing having a shaft extending coaxially androtatably mounted therewithin, the resistance structure being aplurality of vane blades extending laterally from the shaft to thesidewall of the housing, the viscous fluid being contained within thehousing, the housing being mounted to and rotating with the axle, theshaft extending outwardly from the housing, the shaft being fixedlymounted to prevent rotation thereof, whereby the housing rotated aboutthe shaft.
 5. The retractable screen mechanism of claim 4 wherein theviscous material is a hydraulic oil.
 6. The retractable screen mechanismof claim 4 wherein a plurality of ribs extend inwardly from the housingto add turbulence to the flow of the viscous fluid to increase theresistance thereof.
 7. The retractable screen mechanism of claim 6wherein each of the plurality of ribs are bent slightly in one directionto further increase turbulence.
 8. The retractable screen mechanism ofclaim 4 wherein the vane blades curve away from a radial orientation inone direction to further increase turbulence.
 9. The retractable screenmechanism of claim 3 wherein the speed reducer comprises a housinghaving a cap at one end thereof and a jackscrew rotatably receivedwithin the housing, the jackscrew having one end extending through thecap, the housing being filled with the viscous fluid, a disk having oneor more tabs which ride in one or more tracks within the interior of thehousing, the disk being rotatably received on the jackscrew andtraveling upwardly and downwardly along said jackscrew as the jackscrewrotates.
 10. The retractable screen mechanism of claim 9 wherein thehousing is mounted and rotates with the axle, the one end of thejackscrew being fixedly mounted, the housing rotating about the fixedlymounted jackscrew.
 11. The retractable screen mechanism of claim 1wherein the screen material is a fabric.
 12. A retractable screenmechanism for covering an opening, the retractable screen mechanismcomprising: two tracks mounted on opposing sides of the opening, ascreen comprising a screen material mounted on a frame having twoflexible opposing sides corresponding to and adapted to engage the twotracks, a spool mechanism extending between the flexible opposing sidesand engaging a third side of the frame, the screen being adapted to windup on the spool mechanism, the spool mechanism being biased to the windup position, a latch mechanism mounted to a fourth side of frameopposite the third side, the fourth side extending between the twoflexible opposing sides, the latch mechanism engaging a correspondinglatching mechanism mounted on the corresponding side of the opening tolatch the screen in an extended position, the spool mechanism having aspeed reducer comprising a resistance structure moving through a viscousfluid to reduce the speed of the biased screen when moving to the wingup position, the spool mechanism comprising an elongated housing havinga U-shaped profile and a rotating axle contained therein and a platepartially covering the open side end of the elongated housing, theelongated housing and the plate defining a slot, the third side of thescreen extending through the slot to engage the axle, the axle engaginga spring mechanism at one end thereof, the spring mechanism being biasedto hold the screen in the wind up position, the speed reducer beingmounted at the other end of the axle.
 13. The retractable screenmechanism of claim 12 wherein the speed reducer comprises a hollowhousing having a shaft extending coaxially and rotatable mountedtherewithin, a plurality of ribs extend inwardly from the housing to addturbulence to the flow of the viscous fluid to increase the resistancethereof, each of the plurality of ribs being bent slightly in onedirection to further increase turbulence, the resistance structure beinga plurality of vane blades extending laterally from the shaft to thesidewall of the housing, the vane blades curving away from a radialorientation in one direction to further increase turbulence, the viscousfluid being contained within the housing, the housing being mounted toand rotating with the axle, the shaft extending outwardly from thehousing, the shaft being fixedly mounted to prevent rotation thereof,whereby the housing rotates about the shaft.
 14. The retractable screenmechanism of claim 12 wherein the speed reducer comprises a housinghaving a cap at one end thereof and a jackscrew rotatably receivedwithin the housing, the jackscrew having one end extending through thecap, the housing being filled with the viscous fluid, a disk having oneor more tabs which ride in one or more tracks within the interior of thehousing, the disk being rotatably received on the jackscrew andtraveling upwardly and downwardly along said jackscrew as the jackscrewrotates, the housing being mounted and rotating with the axle, the oneend of the jackscrew being fixedly mounted, the housing rotating aboutthe fixedly mounted jackscrew.
 15. A speed reducer for use inretractable screen systems, the speed reducer comprising a resistancestructure moving through a viscous fluid to reduce the speed of thebiased screen when moving to the wind up position.
 16. The speed reducerof claim 15 comprises a hollow housing having a shaft extendingcoaxially and rotatably mounted therewithin, the resistance structurebeing a plurality of vane blades with in the housing, the housing beingmounted to and rotating with the axle, the shaft extending outwardlyfrom the housing, the shaft being fixedly mounted to prevent rotationthereof, whereby the housing rotates about the shaft.
 17. The speedreducer of claim 16 wherein a plurality of ribs extend inwardly from thehousing to add turbulence to the flow of the viscous fluid to increasethe resistance thereof.
 18. The speed reducer of claim 17 wherein eachof the plurality of ribs are bent slightly in one direction to furtherincrease turbulence.
 19. The speed reducer of claim 16 wherein the vaneblades curve away from a radial orientation in one direction to furtherincrease turbulence.
 20. The screen reducer of claim 15 wherein thespeed reducer comprises a housing having a cap at one end thereof and ajackscrew rotatably received within the housing, the jackscrew havingone end extending through the cap, the housing being filled with theviscous fluid, a disk having one or more tabs which ride in one or moretracks within the interior of the housing, the disk being rotatablyreceived on the jackscrew and traveling upwardly and downwardly alongsaid jackscrew as the jackscrew rotates.
 20. The speed reducer of claim19 wherein the housing is mounted and rotates with the axle, the one endof the jackscrew being fixedly mounted, the housing rotating about thefixedly mounted jackscrew.